The present invention is directed generally to a novel mounting or connecting arrangement and more specifically to a self-aligning mounting or connecting arrangement suitable for interconnecting two or more workpieces.
While various uses for the mounting arrangement in accordance with the invention may suggest themselves to those skilled in the art, the disclosure will be facilitated with reference to the problem of securing a mounting bracket to a raised embossment. For example, one or more plastic embossments are often provided as an integral part of a television cabinet, to which certain mounting brackets, for example, the picture tube mounting brackets, must be secured. In many instances there are tolerance discrepancies in the clearance apertures provided in the brackets and embossments, making alignment thereof for the insertion of a suitable fastener difficult or impossible. It will be appreciated that the problem is aggravated when a plurality of relatively fixed brackets must be aligned with like plurality of relatively fixed receiving embossments for the insertion of suitable fasteners therethrough.
It has been proposed to provide a box or other receiving mounting surface without a pilot hole and utilizing a self-tapping type of fastener. However, driving such a fastener requires considerable torque which may result in stripping of the fastener driver head. Moreover, a volume of material substantially equal to the volume of the fastener must be displaced in this operation. Such displacement may occur as a curl of material about the fastener thread which tends to be captured under the fastener head, preventing proper seating of the fastener. Moreover, such extruding of the material tends to shear and weaken the thread form resulting in a lowered strip torque of the completed assembly.
Additionally, considerable stress is imparted by such an operation to the receiving boss or surface, which frequently results in undesirable cracking of the boss or surface. Furthermore, the molding of a relatively large unrelieved boss, i.e., without any pilot hole, often results in uneven cross-sectional thickness, which may be objectional from either a standpoint of structural integrity or as a matter of appearance. Moreover, the amount of torque required to insert a self-tapping screw may result in operator fatigue if a hand-employed driver tool is used.
Various solutions employing enlarged apertures in one of the two workpieces have also been proposed. However, even such enlarged apertures may fail to align properly with facing fastener-receiving bores under many circumstances, particularly when a number of such apertures and bores in each of a pair of relatively fixed surfaces must be aligned and secured. In this regard, even a relatively small amount of misalignment between an aperture and a fastener receiving bore may result in interference from the periphery of the aperture during insertion of a fastener. Such interference may cause stripping and subsequent weakening of the fastener threads. Alternatively, such misalignment may cause uneven pressures to be applied to the bore, resulting in similar problems of insufficient strip torque and/or cracking as discussed above.